The following relates generally to wireless communication, and more specifically to system acquisition in a shared radio frequency spectrum band, such as an unlicensed radio frequency spectrum band.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems (e.g., a Long Term Evolution (LTE) system or a New Radio (NR) system). A wireless multiple-access communications system may include a number of base stations or access network nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Some wireless communications systems may enable communication between a base station and a UE over shared radio frequency spectrum bands, such as an unlicensed radio frequency spectrum band. In some cases, when using a shared radio frequency spectrum band, base stations may perform contention-based channel access by performing a listen before talk (LBT) procedure according to contention-based rules that provide for fair channel access to transmitters that wish to use the shared radio frequency spectrum band. In other cases, base stations using the shared radio frequency spectrum band may transmit according to duty cycle and transmission time requirements to allow for fair channel access. A UE may perform system acquisition with a base station to transmit and receive data over the shared frequency spectrum band.